Trailer Light Tester

Trailer light testers are devices for troubleshooting the wiring of a trailer and tow vehicle in a simple and convenient way. Most testers are small, portable, and are designed for ease of use. Having a plug, a battery, elementary controls, and a few indicators, the tester is pretty simple in its construction, which is why it’s affordable and, normally, works for ages. As well as the light schemes and connectors themselves, trailer light testers are different.

Whereas the simplest, 4-way checker can verify only running lights, brake lights, and turn signals (3 ways + ground), there are devices meant to deal even with 7-way wiring. Besides the four channels mentioned above, such schemes include three extra pins that are typically used for operating the trailer’s separate brake system, providing a 12 volt “hot” lead, and connecting backup lights. Some testers come with attachments to fit multiple kinds of wiring systems; a wide range of adapters is also available.

A trailer light tester, or, to be more specific, a trailer light inline circuit tester, is not actually a necessarily required equipment, as the condition of the trailer’s electrical circuits can be inspected visually without any extra devices. However, this operation requires a tow vehicle to be connected to the trailer, at least two people involved and up to ten minutes spent. Trailer light testers, available in a range of models for any need and budget, allow for quick and trouble-free checks on tow vehicle and trailer wiring separately.

Trailer light inline circuit testers are particularly widely used by commercial fleet operators, those who care about time and safety as part of their business. Heavy commercial semi-trailers are equipped with 7-pin connectors. Having the wires going under the flooring, where they cannot be protected properly, large semi-trailers are even more subjected to electrical malfunctions than personal transportation. That’s the reason why truck drivers must follow the instructions while checking the condition of lights. And those who wonder how to make light troubleshooting simpler and faster often end up with trailer light testers.

Be it a simple 4-way tester for inspecting basic lighting functions or a more sophisticated 7-way device that is able to verify the condition of electric brakes and additional power supply, a light tester is a useful and reliable portable plug-in tool that can make a driver’s life simpler.

About Andrew Demaree

Andrew Demaree is Bully’s resident technical writer and automotive expert. Being SAE certified mechanic, Andrew knows how your vehicle works and how to make it run even smoother. He is also passionate about truck customization and off-roading, so when it comes to adding some style and functionality to your truck, you can rely on Andrew’s knowledge.